I wonder if there is a way to navigate the files with case being insensitive after you press Ctrl-D

I have a bug with navigation: sometimes FileExplorer switching onto another buffers. I'm opening 2 buffers: the right panel is empty, the left panel: FileExplorer. I'm on the left. Type ":e /home/user". Then press "-" (go to up directory). Oops! FileExplorer switching me onto the right panel! :-( What is it?